The invention disclosed herein is an improvement upon the inventions disclosed in prior U.S. Pat. Nos. 3,649,741, issued Mar. 14, 1972, and 3,611,252, issued Oct. 5, 1971. In these patents, a power distribution system is disclosed wherein a U-shaped track carries within the track region elongated molded insulation and bare copper conductors to provide an assembly along which a load circuit power take-off may be established at any desired region along the track length. While the constructions disclosed in these patents have been successful, it has been found desirable to increase the functional possibilities of the track system and provide an adapter for selecting a load circuit from as many as four available power circuits and to indicate such selection.